Numerous tests on biological materials are carried out in an aqueous gel medium. Illustrative test procedures are immunodiffusion, electrophoresis, immunoelectrophoresis and immunological reactions. In such procedures, the aqueous gel, such as agarose, may contain reactants. In general, such test procedures are carried out with aqueous gels contained within glass containers or supported by glass surfaces. Such glass material is not completely satisfactory, since it is quite fragile, resulting in damage to the test apparatus during shipment, storage and/or use.
Efforts have been made in the prior art to replace glass with organoplastic materials, since such organoplastic materials are generally less expensive than glass and are considerably less fragile. Such replacement with organoplastic materials has not been completely satisfactory, because the aqueous gel-forming suspensions and resulting gels do not adhere well to prior art organoplastic support surfaces. This poor adhesion can cause undesirable air bubbles to be formed at the gel-support surface interface when the gel-forming aqueous suspension is spread onto such surface, and the suspension may not flow uniformly over the support surface producing a gel layer having uneven thickness or rippled portions which interfere with subsequent use of the apparatus. In some immunodiffusion reactions test wells are dug out of the gel layer. When there is reduced adherence between the gel layer and the support surface, the entire gel layer can undesirably be lifted away from the support surface during the formation of these test wells. During storage of the test apparatus, the gel layer can tend to become at least partially dehydrated. This dehydration causes a slight shrinking of the gel layer and can cause a prior art organoplastic apparatus to have undesirable separation of the gel layer from the organoplastic support surface.
There is thus a commercial need for biological test apparatus having a uniform close adherent contact between an aqueous gel and an organoplastic support surface.